Main Entry: 1ra·dio
Pronunciation: rd--
Function: noun
Inflected Form(s): plural ra·di·os
Etymology: a shortened form of radiotelegraphy, literally, "telegraphy by rays"; radio- from French radio- "radial, radiating," from Latin radius "ray, beam, spoke" --related to RADIATE, RADIUS, 2RAY1: the sending or receiving of signals using electromagnetic waves without a connecting wire <radio includes television and radar>; especially: the use of these waves to carry sound that has been changed into electrical energy2: a radio receiving set <a transistor radio>3: the radio broadcasting industry